Fermenting Under Pressure

[El Gertez]

I'm surprised no one has mentioned this yet: I ferment lagers under pressure at room temperature. 68 degrees, 15 psi, and fermentation is done in 1-2 weeks.

I ferment in an old sanke keg that I flipped upside down, and cut a hole in the bottom to fit a corny lid. The spear end of the keg mates up nicely to 2 inch TC fittings, so I have attached a blank with a ball valve post mounted to it. I let it ferment with a spunding valve until it's done, and then I use my picnic tap to drain off the yeast/trub until the beer running through the line is clear, then I switch to a keg coupler and transfer under pressure to a serving keg. Works like a charm.

 

[VirginiaHops1]

Are you planning on having your hops in your dry hop keg while it is purged during fermentation? If so, any concerns about your hops sitting a room temp with some O2 for a while? I considered doing something similar to what you are proposing but I worried about having the hops sitting warm in the keg for a while, potentially oxidizing unless the keg was totally purged already.

I tried the mesh on the dip tube along with the keg hopper over the dip tube, as you describe, and it didn't work for me. Tried it several times and somehow hops kept sneaking in there, going up the dip tube, and clogging the poppet. I have no idea how but it did every time. This was in the fermenter though, I wasn't transferring to a separate dry hopping keg.

Yeah, I plan to load and seal the dry hop keg when I pitch and let the fermentation purge it. I've read fermentation can produce 25 volumes or so of CO2 so I would hope that thing is completely scrubbed of O2 by the time I transfer. Not sure if the hops will degrade sitting at room temp but I guess I'll find out. I suspect I may have to do some experimenting to figure out what system works best. The next best method I can think of would be dry hopping in the primary but do it early so there's plenty of activity to scrub the oxygen. I really want to limit my O2 as much as possible though and have already been attempting closed transfers so I'm liking the idea of keg fermenting.

 

[VirginiaHops1]

I'm surprised no one has mentioned this yet: I ferment lagers under pressure at room temperature. 68 degrees, 15 psi, and fermentation is done in 1-2 weeks.

I ferment in an old sanke keg that I flipped upside down, and cut a hole in the bottom to fit a corny lid. The spear end of the keg mates up nicely to 2 inch TC fittings, so I have attached a blank with a ball valve post mounted to it. I let it ferment with a spunding valve until it's done, and then I use my picnic tap to drain off the yeast/trub until the beer running through the line is clear, then I switch to a keg coupler and transfer under pressure to a serving keg. Works like a charm.

There's a bunch of threads here of people fermenting under pressure but I'm not sure it's ideal for IPAs which is what I primarily brew. Creates different yeast flavors. Commercial breweries typically don't even ferment their IPAs under pressure. Your converted corny/conical sounds very cool though.

 

[El Gertez]

There's a bunch of threads here of people fermenting under pressure but I'm not sure it's ideal for IPAs which is what I primarily brew. Creates different yeast flavors. Commercial breweries typically don't even ferment their IPAs under pressure. Your converted corny/conical sounds very cool though.

You're right. I didn't realize from your original post that you were asking specifically with regards to IPAs. I do plan to do an NEIPA with this system soon, just at a low pressure. I will dry hop during primary and then add keg hops to the receiving keg prior to purging and transferring beer into it. Thinking I'll try some sort of bazooka filter/dip tube combo as described above.

 

[Virginia_Ranger]

You're right. I didn't realize from your original post that you were asking specifically with regards to IPAs. I do plan to do an NEIPA with this system soon, just at a low pressure. I will dry hop during primary and then add keg hops to the receiving keg prior to purging and transferring beer into it. Thinking I'll try some sort of bazooka filter/dip tube combo as described above.

This is exactly what I do for all my NEIPAs the only thing I do different (if I'm reading right) is bag all of the hops in separate muslin bags (boiled and then starsans sprayed). I have had zero clogs so far with this method.

 

[sikkingj]

I apologize for resurrecting this thread, but what are the temperatures that people are fermenting their worts at? I have a keg and spundeling valve, but I'm trying to work out how much temperature control I need to exert. Lagers at 68? Ales free rising?

Thanks.

 

[Virginia_Ranger]

I shoot for 65-70 on everything but lagers but I can say the have creeped up to about 72 here and there without I’ll effects. For lagers I try to be really strict on not going over 66 F. Will let it get up to 69 F toward the very end for diacytal rest.

Average lager temp is 63 F

 

[lincolnubrewer]

Is there certain lager yeast better for pressure fermentation and at what temperature is ideal under pressure. What about ale yeasts same questions above. I like to use Mexican lager white lab and have London fog ale yeast wl 066 for hoppy ales.

 

[Robert65]

The point of fermentation under pressure is that the pressure suppresses ester formation even at high temperatures. Therefore any lager yeast can be used, it does not have to be selected for its flavor profile. I've used WLP833 at 15 psig and 65°-°72°F with great success (these are the conditions generally used in commercial pressure fermentation of lagers.) One caveat, these fermentations proceed very quickly, so if you are hoping to increase pressure near the end for full carbonation, it is easy to miss the timing. I've also tried fermenting ales under pressure with very disappointing results. Because of my first point, that pressure suppresses ester formation, the resulting ales are rather dull and characterless. (Scott Janish's blog has information on pressure fermentation of IPA. He found them dull and quite lacking in hop character despite the same hop schedule as control batches.) Also it appears, from my limited experience and from the literature, that ale yeast is more susceptible to adverse effects of pressure, resulting in poor growth, slower fermentation, and underattenuation. My inclination would be to ferment ales at atmospheric pressure and only apply pressure at the end for carbonation.

 

[LBBrewDude]

For the guys who ferment lagers under pressure, what are your experiences with sulfur and/or DMS? I know pressure will suppress esters and other yeast producing flavors and aromas, but from my understanding, sulfur and DMS are driven off into the atmosphere during the production of CO2 during fermentation. So, in theory, by restricting fermentation to a closed, pressurized environment, you would be trapping that sulfur and/or DMS.

 

[Vale71]

If you have detectable DMS in your wort than you need to address the issue in the context of wort production. Fermentation does very little to drive off DMS. Besides that, once pressure is established (which happens very quickly) you will still be venting most of the CO2 like in any open fermentation or the fermenter would explode, so there is hardly any difference between spunding and pressure fermentation in that regard.

 

[Robert65]

If you have detectable DMS in your wort than you need to address the issue in the context of wort production. Fermentation does very little to drive off DMS. Besides that, once pressure is established (which happens very quickly) you will still be venting most of the CO2 like in any open fermentation or the fermenter would explode, so there is hardly any difference between spunding and pressure fermentation in that regard.

^^^^
What he said.

 

[DVCNick]

I used my fermentasaurus for the first time recently and will be transferring to serving keg as soon as I have a keg free up. I ran it completely open most of the time and switched to the pressure lid with spunding just a little fermentation left. Set it at 5 PSI, and could have gone much higher if desired. Next time I'll just use a gas disconnect line into sanitizer the first few days with the pressure kit so I don't have to swap the whole lid.

I specifically made a wheat beer with no dry hops in order to minimize any chances of clogging the first time. But in the event that you clog a poppet with dry hops, what do you do then? Seems like you'd have a bit of a mess on your hands and probably just have to give up and open everything up and siphon?

I haven't had the ability to oxygen-free cold crash before either, and was hoping doing so would drop out all the dry hops out of the way of the floating dip tube, but that doesn't seem to be the consensus in this thread on what is happening.